On 31 August 2010, more than 100 transient luminous events were observed to occur over Typhoon Lionrock when it passed at ∼210 km to the southwest of the NCKU site in Taiwan. Among them, 14 negative gigantic jets (GJs) with clear recognizable morphologies and radio frequency signals are analyzed. These GJs are all found to have negative discharge polarity and thus are type I GJs. Morphologically, they are grouped into three forms: tree‐like, carrot‐like, and a new intermediate type called tree‐carrot‐like GJs. The ULF and ELF/VLF band signals of these events contain clear signatures associated with GJ development stages, including the initiating lightning, the leading jet, the fully developed jet, and the trailing jet. Though the radio waveform for each group of GJs always contains a fast descending pulse linked with the surge current upon the GJ‐ionosphere contact, the detailed waveforms actually vary substantially. Cross analysis of the optical and radio frequency signals for these GJs indicates that a large surge current moment (CM) (>60 kA‐km) appears to be essentially associated with the tree‐like GJs. In contrast, the carrot‐like and the tree‐carrot‐like GJs are both related to a surge CM less than 36 kA‐km, and a continuing CM less than 27 kA‐km further separates the carrot‐like GJs from the tree‐carrot‐like GJs. Furthermore, on the peak CM versus charge moment change diagram for the initiating lightning, different groups of GJs seem to exhibit different trends. This feature suggests that the eventual forms of negative GJs may have been determined at the initiating lightning stage.

Surfactants have been used often in environmental remediation strategies due to their special amphiphilic nature which alters surface and water interfacial properties. When the aqueous concentration of a cationic surfactant far exceeds the critical micelle concentration (CMC), a large concentration of cationic micelles will form in water. These micelles each consist of tens to hundreds of surfactant monomers, and collectively can be utilized as nano-sized ion exchangers to assist with ultrafiltration separation (i.e., removal) of anionic pollutants from natural waters or wastewaters. Target anionic pollutants include nitrate, phosphate, arsenate and chromate. However, most polluted waters contain a complex mixture of anions, with these different anions competing for the micellar pseudo-phase, thus potentially reducing the overall removal efficiency of the target anions.Further, loss of surfactant monomers through the membrane also reduces process efficiency as replenishment of surfactant over time is required. In this review, the existing research on inorganic anion removal by micellar enhanced ultrafiltration (MEUF) and similar processes

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